Interstitial Lung Disease

Question 1

What types of cells are found in the pulmonary interstitium?

Answer 1

• Type I and II alveolar cells

- Thin elastin-rich connective tissue (contains capillaries)

Question 2

Describe the difference between early and late stage Interstitial Lung Disease?

Answer 2

Early stage = alveolitis (injury with inflammatory cell infiltration)

Late stage = fibrosis

Question 3

What are the potential causes of ILD?

Answer 3

• Environmental (minerals, drugs etc)
• Hypersensitivity (mouldy hay, avian proteins)
• Unknown (idiopathic e.g. IPF)
• Due to Connective tissue diseases

Question 4

HOw is a biopsy completed when you suspect ILD in a patient?

Answer 4

Transbronchial biopsy – special forceps used at bronchoscopy

Thoracoscopic biopsy – more invasive but gets more tissue

Question 5

Which types of interstitial lung disease are chronic?

Answer 5

• Idiopathic pulmonary fibrosis (IPF)
• Sarcoidosis
• Hypersensitivity pneumonitis (extrinsic allergic alveolitis)
• Pneumoconiosis
• Connective tissue diseases

Question 6

How does Idiopathic pulmonary fibrosis appear pathologically?

Answer 6

• Subpleural and basal fibrosis (HONEYCOMBING)
• may be associated inflammation
• Terminal disease shows lung replaced by dilated spaces AND whole thing surrounded by fibrous walls

Question 7

What sign in the hands can be caused by idiopathic pulmonary fibrosis?

Answer 7

Finger clubbing

Question 8

What is Hypersensitivity Pneumonitis/ Extrinsic Allergic ALveolitis?

Answer 8

Chronic inflammatory disease (not fibrotic)
Affects:
- Small airways
- Interstitium
- Causes occasional granulomas

Question 9

What can cause Hypersensitivity Pneumonitis/ Extrinsic Allergic Alveolitis?

Answer 9

• Thermophilic bacteria – Farmers lung
• Avian proteins – Bird fanciers lung
• Fungi – Malt workers lung

Question 10

What is sarcoidosis?

Answer 10

• Granulomas form in many body systems
• cause is unknown
• Pulmonary involvement is common
• Most cases mild and self-limiting
• granulomas are non-caseating (difference from TB)

Question 11

Aside from granulomas, what else does sarcoidosis cause?

Answer 11

• Uveitis (inflammation of iris)
• Erythema nodosum (skin)
• Lymphadenopathy (especially in hilum of lungs)
• Hypercalcaemia

Question 12

What pulmonary effects do connective tissue diseases cause?

Answer 12

• Interstitial fibrosis (milder than IPF)
• Pleural effusions
• Rheumatoid nodules (can be seen on CXR)

Question 13

What is pneumoconiosis and what can cause this condition?

Answer 13

• lung disease caused by mineral dust exposure:
• Asbestosis
• Coal workers lung
• Silicosis

Question 14

What does the degree of pneumoconiosis depend on?

Answer 14

• Particle size (1-5mm)
• Reactivity of particle
• Clearance of particle
• Host response

Question 15

Does ILD cause an obstructive or restrictive lung disease pattern on spirometry?

Answer 15

RESTRICTIVE

Question 16

Describe the difference between acute and chronic sarcoidosis

Answer 16

ACUTE

• erythema nodosum
• bilateral hilar lymphadenopathy
• arthritis
• uveitis
• fever

CHRONIC

• lung infiltrates
• peripheral lymphadenopathy
• hypercalcaemia
• Other organs: renal, myocardial, neurological, hepatitis, splenomegaly

Question 17

What are the potential differential diagnoses for sarcoidosis?

Answer 17

• TB (tuberculin test -ve)
• Lymphoma
• Carcinoma
• fungal infection

Question 18

How is chronic sarcoidosis treated?

Answer 18

ACUTE

• supportive Tx as self limiting
• oral steroids if vital organs are affected

CHRONIC

• steroids
• immunosuppression

Question 19

What type of Hypersensitivity reaction is responsible for extrinsic allergic alveolitis?

Answer 19

Type III

- immun complexes deposited in lung tissue

Question 20

How does Acute EAA present?

Answer 20

• cough, breathless, fever, myalgia –
• SOB
• fever
• myalgia
• come on a few hrs after exposure

Question 21

How does Chronic EAA present?

Answer 21

• progressive breathlessness and cough
• crackles in chest
• CXR pulmonary fibrosis in the upper zones
• Restrictive defect

Question 22

How does idiopathic pulmonary fibrosis present?

Answer 22

• progressive breathlessness
• dry cough
• clubbing
• bilateral fine inspiratory crackles
• restrictive defect
• CxR = bilateral infiltrates
• CT scan = fibrotic shadowing, worse at the lung bases

Question 23

What differentials should you check for before diagnosing a patient with IPF?

Answer 23

• occupational disease (asbestosis, silicosis)
• connective tissue disease (RhA, scleroderma, Sjogrens Disease, SLE)
• left ventricular failure
• sarcoidosis
• extrinsic allergic alveolitis

Question 24

How is IPF treated?

Answer 24

• Steroids and immunosuppressants do NOT change course of disease

=> New antifibrotic drugs – PIRFENIDONE and NINTEDANIB

• these slow disease progression but dont reverse fibrosis
• very expensive
• Give O2 if pt is hypoxic
• Lung transplantation in young patients

Question 25

What is the difference between simple and complicated pneumoconiosis?

Answer 25

Simple - CXR abnormality but lung function normal Complicated - massive fibrosis (often in upper zone) causes breathlessness and restrictive pattern

Question 26

Prolonged asbestos exposure can cause pulmonary fibrosis. TRUE/FALSE?

Answer 26

TRUE - “Asbestosis” - Diffuse pulmonary fibrosis - restrictive defect - Asbestos bodies in sputum - Asbestos fibres in lung biopsy